Remove "Documentation currently incomplete and in draft status" note from editor manual

It's no more 'unfinished' than anything else in Wagtail...

docs/editor_manual/index.rst

@@ -3,9 +3,6 @@
 Using Wagtail: an Editor's guide
 ================================
 
-.. note::
-	Documentation currently incomplete and in draft status
-
 This section of the documentation is written for the users of a Wagtail-powered site. That is, the content editors, moderators and administrators who will be running things on a day-to-day basis.
 
 .. toctree::